Thermoplastic synthetic polymers are well-known for the desirable characteristics of moldability and processing with techniques which are especially suited for the mass production of various articles from such polymers. However, many thermoplastic polymers by their very nature are often not useable in applications requiring relatively high use temperatures. In recent years various thermoplastic polymers have been developed which can be employed at relatively high temperatures and under corrosive conditions. Such thermoplastic polymers generally have a relatively high melting or softening point that provides the enhanced high temperature resistance of articles prepared therefrom.
A continuing problem remains, however, in that the molecular weight and melt stability of such heat resistant thermoplastic polymers is often inadequate to maintain a good balance of physical properties in the final article produced from the polymer. In particular, when it is desired to make biaxially-oriented film from such polymers, it is necessary that the molecular weight and the stability of the thermoplastic polymer be adequate for the production of useful biaxially-oriented film having good physical properties. Thus, methods of producing such thermoplastic heat-resistant polymers of suitable molecular weight and stability for the production of biaxially-oriented films are still being sought.
Aromatic sulfide/ketone polymers are known in the art as having high crystalline melting points and are thus desired in applications requiring a high use temperature. Such applications include, for example, coatings for electrical wiring, automotive parts, aircraft parts, and the like. Biaxially-oriented film obtained from aromatic sulfide/ketone polymers is especially useful in applications such as electrical insulation and the like.
It is an object of our invention to provide a process for producing aromatic sulfide/ketone polymers. It is a further object of our invention to provide a process for producing aromatic sulfide/ketone polymers of high molecular weight and good melt stability. It is a still further object of our invention to provide a simple and readily controllable process for producing aromatic sulfide/ketone polymers of high molecular weight and good melt stability. It is also an object of our invention to provide a process for producing biaxially-oriented film from aromatic sulfide/ketone polymers of high molecular weight and good melt stability which are made by our inventive process.